Different control systems for the ignition of a burner in domestic gas appliances are already known. In some of the systems an incandescent element or an igniter (a glowbar) is used for such a purpose. The incandescent element is disposed adjacent to the burner and is heated up to a temperature suitable for gas combustion, the incandescent element causing, when it reaches the temperature, the gas that reaches the burner to light.
U.S. Pat. No. 3,826,605 discloses a control system of this type, the control system comprising a thermoelectric valve to enable the passage of gas towards the burner. The thermoelectric valve comprises a bimetallic element and a resistive element that keeps the passage of gas closed at ambient temperature, this being opened when the bimetallic element is heated by the power supply current of the igniter. The choice of material of the elements and their arrangement is essential in ensuring the system functions correctly and that the valve does not open too early, for example, or open too late after the incandescent element has reached the combustion temperature. In addition, as it is dependent upon the temperature of the elements in order to close, the thermoelectric valve may remain open for a period of time after the command to switch off the burner has been sent, with gas reaching the burner during the period of time. In a second embodiment disclosed in the document, the control system also comprises an electromagnetic valve, it being necessary for both the thermoelectric and the electromagnetic valve to be open to enable the passage of gas. The thermoelectric valve continues to control the opening of the passage of gas, whereas the electromagnetic valve controls the closure of the passage.